1. Field of the Invention
The present invention relates to a flat connector for transmitting driving power to an electric device, and a method of manufacturing the flat connector. The present invention also relates to an ink jet head that uses the flat connector, and a method of manufacturing the ink jet head.
2. Description of the Related Art
An ink jet printer provided with an ink jet head and a flat connector is taught in Japanese Laid Open Utility Model Publication No. 1992-33550 (H4-33550). Ink is stored within the ink jet head. The ink jet head is provided with piezo-electric elements and contacts. The piezo-electric elements apply pressure to the ink. The contacts are connected with the piezo-electric elements, and are distributed on a surface of the ink jet head. The flat connector is provided with an insulating base film, and a conductive pattern formed on a surface of the base film. The conductive pattern has conductive spots and conductive lines. Each conductive line is connected with each conductive spot, respectively. The conductive spots of the flat connector are located opposite the contacts of the ink jet head.
Each conductive spot is formed as a projection that protrudes towards one of the contacts of the ink jet head. The flat connector is pressed against the ink jet head by a resilient member, thus connecting the conductive spots of the flat connector—these conductive spots being formed as projections—with the contacts of the ink jet head. A connection is thus completed to transmit driving power to the piezo-electric elements of the ink jet head. The base film of the flat connector is flexible, and is termed an FPC (Flexible Printed Circuit).
In the aforementioned ink jet printer, the base film of the flat connector is extremely thin, and it is therefore difficult to handle. That is, the flat connector bends readily when the conductive spots of the flat connector are made to overlap with the contacts of the ink jet head, and therefore the flat connector is difficult to handle. The flat connector can be handled more easily if the base film is thicker. However, when a thick base film is used and the projections of conductive spots are formed, each of these projections becomes larger, and it is therefore difficult to distribute the conductive spots with a high density. Further, the projecting parts of the conductive spots lose flexibility due to the base film being thicker. As a result, when there is unevenness among the heights of the projections of the flat connector or among the heights of the contacts of the ink jet head, there may be locations where the conductive spots of the flat connector do not make contact with the contacts of the ink jet head.